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the slowest reaction in a sequence is the - ANSWER rate-limiting step the state of a system in which no further net change is occurring - ANSWER equilibrium the assumption that the rate of formation of ES is exactly equal to the rate of breakdown of ES is called the _____ _____ assumption - ANSWER steady state K cat is known as the _____ number. at saturating substrate concentrations, kcat=vmax/[Et] - ANSWER turnover number type of inhibitor that alters the Km of an enzyme without altering vmax - ANSWER competitive molecule that binds to the active sit of an enzyme - ANSWER substrate Relatively small portion of an enzyme that is involved in substrate binding - ANSWER active site Describes changes in the conformation of an enzyme upon substrate binding - ANSWER induced fit
A ____-_____ analog binds more tightly to the active sit than does the substrate molecule - ANSWER transition state ______-______ kinetics describes the enzymatic activity of an idealized enzyme - ANSWER Michaelis menten Trypsin is to trypsinogen as active enzyme is to - ANSWER zymogen Complete enzyme complex containing all the protein subunits and prosthetic groups - ANSWER holoenzyme Type of energy obtained from the interaction of enzyme and substrate that decreases the activation energy for a reaction - ANSWER binding A binding site of a protein is structurally complementary to a specific ligand because of what characteristic of the binding site? - ANSWER Size Shape Charge Hydrophobicity Which of the following molecules is bound MOST strongly to the heme iron? - ANS CO Which amino acid in hemoglobin is a ligand to iron in addition to the heme prosthetic group? - ANS Histamine Hemoglobin participates in the transportation of which ion and/or molecule in the blood? - ANS CO2, O2, and H+
C. Oxidoreductases D. Polymerases E. Transferases - ANSWER Polymerases The function of an enzyme in an enzymatic reaction is to: A) Bind a transition state intermediate, such that it cannot be converted back to substrate. B) Ensure that all of the substrate is converted to product. C) Ensure that the product is more stable than the substrate. D) Increase the rate at which substrate is converted into product. E) make the free-energy change for the reaction more favorable. - ANSWER D. Increase the rate at which substrate is converted into product Enzymes differ from other catalysts in that only enzymes - ANSWER display specificity toward a single reactant The lineweaver-Burk plot is used to - ANSWER solve graphically, for the rate of an enzymatic reaction at an infinite substrate concentration To calculate Km from a doublereciprocal plot you would - ANSWER multiply the reciprocal of the xaxis intercept by - 1 To calculate the turnover number of an enzyme you must know - ANSWER Both the enzyme concentration and the initial velocity of the catalyzed reaction at [S]>>Km
The number of substrate molecules converted to product in a given unit of time by a single enzyme molecule at saturation is referred to as the: - ANSWER turnover number In competitive inhibition, an inhibitor - ANSWER binds reversibly at the active site Vmax for an enzyme-catalyzed reaction - ANSWER is twice the rat observed when the concentration of substrate is equal to the Km An enzyme that can convert glucose into fructose is a member of what class of enzymes? - ANSWER isomerases An uncompetitive inhibitor binds to the enzyme - ANSWER It reversibly binds to the enzyme-substrate complex but does not bind to the free enzyme. What type of enzyme will phosphorylate certain amino acids? - ANSWER a protein kinase The process of ____ converts glucose to _______ - ANSWER glycolysis; pyruvate What pathway is used to synthesize glucose from other metabolites such as oxaloacetate? - ANSWER gluconeogenesis In eukaryotes, glycolysis typically occurs in the ____ gluconeogenesis typically occurs in the _____ - ANSWER cytosol, cytosol
